More than 1.8 million people have fled to neighbouring countries since South Sudan war erupted in 2013.

Unicef warns of famine in South Sudan affecting one million peopleUNICEF

The United Nations has called on donors to step up support for people fleeing war-torn South Sudan, claiming the $1.4 bn ( £1bn) project to help refugees remains largely unfunded.

Humanitarian organisations are seeking funds to provide life-saving support to people displaced by war, famine and a drought, but at least 86% ($1.2bn out of $1.4 bn) of the money needed is still lacking.

"Bitter conflict and deteriorating humanitarian conditions in South Sudan are driving people from their homes in record numbers," the UN High Commissioner for Refugees and the World Food Programme said in a joint statement on Monday (15 May).

The UN has deemed the displacement deriving from South Sudan war as the world's fastest growing refugee crisis, with more than 1.8 million people – of whom one million are children – having fled to neighbouring countries.

The organisation also said the number of people fleeing has exceeded estimates. For example, the number of people who sought refuge in Sudan in March, surpassed the figure estimated for the whole year.